Various medical conditions are characterized by accumulation of liquids under or behind the skin surface. Such conditions may include otitis media, pressure ulcers, or other types of deep tissue injury under intact skin.
Medications or other substances may be introduced or delivered into the bloodstream. For example, a substance may be delivered orally to a patient, or may be injected into tissue or via an intravenous infusion. In some cases, it is important to monitor the concentration or amount of the substance in a patient's blood or tissue. Monitoring the concentration or the amount may include drawing a blood or tissue sample from the patient.
In order to provide respiratory and cardiovascular support for patients undergoing medical procedures, as well as monitoring the vital signs of the patient, anesthesiologists need to properly monitor the anesthetics. The degree of anesthesia reflects the degree of blockade of sensory, reflex, mental, and/or motor functions, which can be achieved by using inhalational agents and/or intravenous anesthetics. Current methods cannot provide precise determination of the degree of anesthesia and/or the concentration of anesthetic agents in the blood stream and/or precisely determine the drug quantity required to provide a sufficient “degree of anesthesia”.
Propofol is a short-acting intravenously administered anesthetic that is most commonly used for induction and maintenance of general anesthesia and for procedural sedation. For example, it can be used in a regimen that provides hypnosis, analgesia and muscle relaxation. Propofol is usually administered as a constant intravenous infusion in order to deliver and maintain a specific plasma concentration. It is therefore desirable to evaluate plasma concentrations in real time to accurately maintain anesthetic efficacy. Currently there is no clinically useful method for measuring blood Propofol concentrations on line and in real time.